canvas实现城市烟花特效-html代码-BFW代码库

代码语言：html
所属分类：粒子
下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">

<title>Canvas Fireworks</title>

<style>
      html, body {
	margin: 0;	
	padding: 0;
}

body {
	background: #171717;
	color: #999;
	font: 100%/18px helvetica, arial, sans-serif;
}

a {
	color: #2fa1d6;
	font-weight: bold;
	text-decoration: none;
}

a:hover {
	color: #fff;	
}

#canvas-container {
	background: #000 url(http://repo.bfw.wiki/bfwrepo/images/bg.jpg);
  height: 400px;
	left: 50%;
	margin: -200px 0 0 -300px;
	position: absolute;
	top: 50%;
  width: 600px;
	z-index: 2;
}
		
canvas {
	cursor: crosshair;
	display: block;
	position: relative;
	z-index: 3;
}

canvas:active {
	cursor: crosshair;
}

#skyline {
	background: url(http://repo.bfw.wiki/bfwrepo/images/skyline.png) repeat-x 50% 0;
	bottom: 0;
	height: 135px;
	left: 0;
	position: absolute;
	width: 100%;
	z-index: 1;	
}

#mountains1 {
	background: url(http://repo.bfw.wiki/bfwrepo/images/mountains1.png) repeat-x 40% 0;
	bottom: 0;
	height: 200px;
	left: 0;
	position: absolute;
	width: 100%;
	z-index: 1;	
}

#mountains2 {
	background: url(http://repo.bfw.wiki/bfwrepo/images/mountains2.png) repeat-x 30% 0;
	bottom: 0;
	height: 250px;
	left: 0;
	position: absolute;
	width: 100%;
	z-index: 1;	
}

#gui {
	right: 0;
	position: fixed;
	top: 0;
	z-index: 3;
}
    </style>

<script src="http://repo.bfw.wiki/bfwrepo/js/prefixfree.min.js"></script>

</head>
<body translate="no">
<div id="gui"></div>
<div id="canvas-container">
<div id="mountains2"></div>
<div id="mountains1"></div>
<div id="skyline"></div>
</div>

<script src='http://repo.bfw.wiki/bfwrepo/js/jquery.17.js'></script>
<script src='http://repo.bfw.wiki/bfwrepo/js/dat.gui.min.js'></script>
<script>
      var Fireworks = function () {
  /*=============================================================================*/
  /* Utility
                                                                                    /*=============================================================================*/
  var self = this;
  var rand = function (rMi, rMa) {return ~~(Math.random() * (rMa - rMi + 1) + rMi);};
  var hitTest = function (x1, y1, w1, h1, x2, y2, w2, h2) {return !(x1 + w1 < x2 || x2 + w2 < x1 || y1 + h1 < y2 || y2 + h2 < y1);};
  window.requestAnimFrame = function () {return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (a) {window.setTimeout(a, 1E3 / 60);};}();

  /*=============================================================================*/
  /* Initialize
                                                                                    /*=============================================================================*/
  self.init = function () {
    self.canvas = document.createElement('canvas');
    self.canvasContainer = $('#canvas-container');

    var canvasContainerDisabled = document.getElementById('canvas-container');
    self.canvas.onselectstart = function () {
      return false;
    };

    self.canvas.width = self.cw = 600;
    self.canvas.height = self.ch = 400;

    self.particles = [];
    self.partCount = 30;
    self.fireworks = [];
    self.mx = self.cw / 2;
    self.my = self.ch / 2;
    self.currentHue = 170;
    self.partSpeed = 5;
    self.partSpeedVariance = 10;
    self.partWind = 50;
    self.partFriction = 5;
    self.partGravity = 1;
    self.hueMin = 150;
    self.hueMax = 200;
    self.fworkSpeed = 2;
    self.fworkAccel = 4;
    self.hueVariance = 30;
    self.flickerDensity = 20;
    self.showShockwave = false;
    self.showTarget = true;
    self.clearAlpha = 25;

    self.canvasContainer.append(self.canvas);
    self.ctx = self.canvas.getContext('2d');
    self.ctx.lineCap = 'round';
    self.ctx.lineJoin = 'round';
    self.lineWidth = 1;
    self.bindEvents();
    self.canvasLoop();

    self.canvas.onselectstart = function () {
      return false;
    };


  };

  /*=============================================================================*/
  /* Particle Constructor
                                                                                    /*=============================================================================*/
  var Particle = function (x, y, hue) {
    this.x = x;
    this.y = y;
    this.coordLast = [
    { x: x, y: y },
    { x: x, y: y },
    { x: x, y: y }];

    this.angle = rand(0, 360);
    this.speed = rand(self.partSpeed - self.partSpeedVariance <= 0 ? 1 : self.partSpeed - self.partSpeedVariance, self.partSpeed + self.partSpeedVariance);
    this.friction = 1 - self.partFriction / 100;
    this.gravity = self.partGravity / 2;
    this.hue = rand(hue - self.hueVariance, hue + self.hueVariance);
    this.brightness = rand(50, 80);
    this.alpha = rand(40, 100) / 100;
    this.decay = rand(10, 50) / 1000;
    this.wind = (rand(0, self.partWind) - self.partWind / 2) / 25;
    this.lineWidth = self.lineWidth;
  };

  Particle.prototype.update = function (index) {
    var radians = this.angle * Math.PI / 180;
    var vx = Math.cos(radians) * this.speed;
    var vy = Math.sin(radians) * this.speed + this.gravity;
    this.speed *= this.friction;

    this.coordLast[2].x = this.coordLast[1].x;
    this.coordLast[2].y = this.coordLast[1].y;
    this.coordLast[1].x = this.coordLast[0].x;
    this.coordLast[1].y = this.coordLast[0].y;
    this.coordLast[0].x = this.x;
    this.coordLast[0].y = this.y;

    this.x += vx;
    this.y += vy;

    this.angle += this.wind;
    this.alpha -= this.decay;

    if (!hitTest(0, 0, self.cw, self.ch, this.x - this.radius, this.y - this.radius, this.radius * 2, this.radius * 2) || this.alpha < .05) {
      self.particles.splice(index, 1);
    }
  };

  Particle.prototype.draw = function () {
    var coordRand = rand(1, 3) - 1;
    self.ctx.beginPath();
    self.ctx.moveTo(Math.round(this.coordLast[coordRand].x), Math.round(this.coordLast[coordRand].y));
    self.ctx.lineTo(Math.round(this.x), Math.round(this.y));
    self.ctx.closePath();
    self.ctx.strokeStyle = 'hsla(' + this.hue + ', 100%, ' + this.brightness + '%, ' + this.alpha + ')';
    self.ctx.stroke();

    if (self.flickerDensity > 0) {
      var inverseDensity = 50 - self.flickerDensity;
      if (rand(0, inverseDensity) === inverseDensity) {
        self.ctx.beginPath();
        self.ctx.arc(Math.round(this.x), Math.round(this.y), rand(this.lineWidth, this.lineWidth + 3) / 2, 0, Math.PI * 2, false);
        self.ctx.closePath();
        var randAlpha = rand(50, 100) / 100;
        self.ctx.fillStyle = 'hsla(' + this.hue + ', 100%, ' + this.brightness + '%, ' + randAlpha + ')';
        self.ctx.fill();
      }
    }
  };

  /*=============================================================================*/
  /* Create Particles
                                                                                    /*=============================================================================*/
  self.createParticles = function (x, y, hue) {
    var countdown = self.partCount;
    while (countdown--) {
      self.particles.push(new Particle(x, y, hue));
    }
  };

  /*=============================================================================*/
  /* Update Particles
                                                                                    /*=============================================================================*/
  self.updateParticles = function () {
    var i = self.particles.length;
    while (i--) {
      var p = self.particles[i];
      p.update(i);
    };
  };

  /*=============================================================================*/
  /* Draw Particles
                                                                                    /*=============================================================================*/
  self.drawParticles = function () {
    var i = self.particles.length;
    while (i--) {
      var p = self.particles[i];
      p.draw();
    };
  };

  /*=============================================================================*/
  /* Firework Constructor
                                                                                    /*=============================================================================*/
  var Firework = function (startX, startY, targetX, targetY) {
    this.x = startX;
    this.y = startY;
    this.startX = startX;
    this.startY = startY;
    this.hitX = false;
    this.hitY = false;
    this.coordLast = [
    { x: startX, y: startY },
    { x: startX, y: startY },
    { x: startX, y: startY }];

    this.targetX = targetX;
    this.targetY = targetY;
    this.speed = self.fworkSpeed;
    this.angle = Math.atan2(targetY - startY, targetX - startX);
    this.shockwaveAngle = Math.atan2(targetY - startY, targetX - startX) + 90 * (Math.PI / 180);
    this.acceleration = self.fworkAccel / 100;
    this.hue = self.currentHue;
    this.brightness = rand(50, 80);
    this.alpha = rand(50, 100) / 100;
    this.lineWidth = self.lineWidth;
    this.targetRadius = 1;
  };

  Firework.prototype.update = function (index) {
    self.ctx.lineWidth = this.lineWidth;

    vx = Math.cos(this.angle) * this.speed,
    vy = Math.sin(this.angle) * this.speed;
    this.speed *= 1 + this.acceleration;
    this.coordLast[2].x = this.coordLast[1].x;
    this.coordLast[2].y = this.coordLast[1].y;
    this.coordLast[1].x = this.coordLast[0].x;
    this.coordLast[1].y = this.coordLast[0].y;
    this.coordLast[0].x = this.x;
    this.coordLast[0].y = this.y;

    if (self.showTarget) {
      if (this.targetRadius < 8) {
        this.targetRadius += .25;
      } else {
        this.targetRadius = 1;
      }
    }

    if (this.startX >= this.targetX) {
      if (this.x + vx <= this.targetX) {
        this.x = this.targetX;
        this.hitX = true;
      } else {
        this.x += vx;
      }
    } else {
      if (this.x + vx >= this.targetX) {
        this.x = this.targetX;
        this.hitX = true;
      } else {
        this.x += vx;
      }
    }

    if (this.startY >= this.targetY) {
      if (this.y + vy <= this.targetY) {
        this.y = this.targetY;
        this.hitY = true;
      } else {
        this.y += vy;
      }
    } else {
      if (this.y + vy >= this.targetY) {
        this.y = this.targetY;
        this.hitY = true;
      } else {
        this.y += vy;
      }
    }

    if (this.hitX && this.hitY) {
      var randExplosion = rand(0, 9);
      self.createParticles(this.targetX, this.targetY, this.hue);
      self.fireworks.splice(index, 1);
    }
  };

  Firework.prototype.draw = function () {
    self.ctx.lineWidth = this.lineWidth;

    var coordRand = rand(1, 3) - 1;
    self.ctx.beginPath();
    self.ctx.moveTo(Math.round(this.coordLast[coordRand].x), Math.round(this.coordLast[coordRand].y));
    self.ctx.lineTo(Math.round(this.x), Math.round(this.y));
    self.ctx.closePath();
    self.ctx.strokeStyle = 'hsla(' + this.hue + ', 100%, ' + this.brightness + '%, ' + this.alpha + ')';
    self.ctx.stroke();

    if (self.showTarget) {
      self.ctx.save();
      self.ctx.beginPath();
      self.ctx.arc(Math.round(this.targetX), Math.round(this.targetY), this.targetRadius, 0, Math.PI * 2, false);
      self.ctx.closePath();
      self.ctx.lineWidth = 1;
      self.ctx.stroke();
      self.ctx.restor.........完整代码请登录后点击上方下载按钮下载查看